The very first thing I do after installing a new version of Mathematica is setting up keyboard shortcuts for typing the double brackets you get with ESC [[ ESC.
You can find the file named KeyEventTranslations.tr in the installation directory and add the following after the line EventTranslations[{
Item[KeyEvent["[", Modifiers -> {Command}], FrontEndExecute[{FrontEnd`NotebookWrite[FrontEnd`InputNotebook[], "\[LeftDoubleBracket]", After]}]],
Item[KeyEvent["]", Modifiers -> {Command}], FrontEndExecute[{FrontEnd`NotebookWrite[FrontEnd`InputNotebook[], "\[RightDoubleBracket]", After]}]],
Do make a backup of the file before doing any modifications and put the backup outside of the Mathematica installation directory (or at least make sure you don't add extra files with a .tr extension).
On Windows/Linux I use the Control modifier instead of Command.
Now you can use Command-[ and Command-] to type these double brackets. I'm so used to this at this point that I almost can't work at all with Mathematica without this modification.